* ci: skip building unused E2E suite binaries in e2e.yml's single/multi jobs
These two jobs immediately rebuild suite-aware binaries after Build
Install Artifacts and never consume the tar's _bin contents, so the
cross-compiled suite build was pure waste. build-install-artifacts.sh
gains an optional --skip-e2e-build flag (positional contract unchanged);
e2e-nightly.yml and the other callers keep building the full set.
* refactor: replace hand-rolled IMDS client with AWS SDK v2
internal/imdscreds, cmd/ecs-agent's metadata fetch and its credentials
provider used a hand-written IMDSv2 token/GET flow with manual RFC3339
expiry parsing. A malformed Expiration silently fell back to "never
expires" instead of failing.
Replace it with feature/ec2/imds, credentials/ec2rolecreds and
aws.CredentialsCache, following the internal/gwsign/signer.go
precedent. An unparseable Expiration is now a hard error from Fetch,
covered by TestFetch_BadExpirationErrors. Output shapes to callers are
unchanged, and IMDS base URLs ending in /latest keep working.
* refactor: derive predastore bind config from spinifex.toml in spx itself
predastore-start.sh awk-parsed spinifex.toml for the bind host/port and
node_id, exported them as env vars, then exec'd spx. Move that
derivation into predastoreStartCmd via derivePredastoreBind, which
reads the raw (non-DIAL-normalized) nodes.<node>.predastore section,
defaulting node_id to -1 (co-located) when the key is absent, same as
the script. An explicit --host/--port/--node-id flag or
SPINIFEX_PREDASTORE_* env var still overrides the derived value.
Delete the now-unused script and point the systemd unit's ExecStart
directly at spx service predastore start, matching the
spinifex-viperblock.service precedent.
Julian Sommer